For Caribbean box jellyfish, learning is literally a no-brainer. In a new experiment, these animals learned to spot and avoid obstacles despite having no central brain, researchers report September 22 ...

We’re celebrating 180 years of Scientific American. Explore our legacy of discovery and look ahead to the future. Billions of nerve cells send signals coursing through our bodies, serving as conduits ...

A complex system of nerves and muscles enables the human eye to blink, gaze, and shift focus. The trochlear nerve is one of six cranial nerves that carry electrical impulses from the brain to the eye.